Got under the hood of my new to me 240 finally this weekend. Did the usual, plugs, cleaned cap and rotor, cleaned throttle body, flame trap, air filter, checked the vacuum hoses. It ran before, but was rough and jumpy and just generally funky. Now, I have a high idle. I think my idle control valve is dead, it is a 0280140501, which I'm lead to believe is the same as a spare 0280140520 I have around and installed. Now, with the blue white wire jumped to ground, with the throttle body stop screw turned till it's just touching the lever, and the adjustment knob all the way in, it's still idling with no load in park at 900rpm or so. I can put it in gear with lights on and fan on and get the idle to drop to 680 or so, bump it up to 700 with the adjustment knob, THEN when pulling the jumper off to re-activate the idle control valve there is some action.
But it's still too high in park. I don't find a vacuum leak, it seems to run well and smooth. It can't be the ICV I don't think, since when it's jumpered it's closed, or is supposed to be. What else will give a high but good idle on these?